"cavelamb himself" wrote in message
...
Peter Dohm wrote:

Actually, I did have a car a while back with one of those rear window
brake
lights that eventually failed. For no obvious reason, the replacement
bulb
(of the same physical size and generic part number) quickly burned
through
the top of the plastic casing--despite having a peice of foil (which was
original equipment) directly above the bulb. That was also in the 1amp
range at 12-14 volts; but I believe that the clearance was closer to a
quarter inch.

A strobe should generate much less heat, especially localized heat, than
an
incandescent bulb; but this is a good problem to keep in mind for nav
lights. Of course, LEDs have become an affordable and reliable
alternative
that also eliminate much of the heating problem--especially if the
current
source is remotely located.

Peter



Peter,

I just happened to have the plug and one of the "experiments" on hand.

Guess I need to revise the clearance question to LESS than 1/2 inch.

This one, I believe, is polycarbinate (DUE TO THE LACK OF BUBBLES IN THE
PLASTIC).

The lexan attempts were made with .065 scrap from my windshield.
Every one of those bubbled like crazy in the baking phase.

Lexan is hydroscopic and retains considerable water.
This stuff "boils" out while heating unless "baked" out at below 212
for several hours. It was kinda pretty with the colored light on inside
it. But not exactly the sleek smooth aircraft parts I had in mind...

Pic at:
http://www.home.earthlink.net/~cavel...sc.htm#wingtip

More clearance, thicker plastic, maybe they use some kind of special
stuff - I really dunno there.

Just that thin stuff with a fairly hot bulb simply didn't work...

YMMV

Richard

I am not really sure why, but I was thinking of the type of lens that ends
up being an entire corner of a wing, so that it has a lot of volume and a
lot of area. Now that I have thought about it, 12 to 14 watts is a *lot* of
heat for this size lens.

I am not sure what material is used in the currently offered commercial
assemblies, but it may very well be glass. (As you might guess, I also
don't know what material to use as a mold for glass--much less how to form
the resulting mold.)

Peter